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Initial Oxidation Structure of Chlorinated Si(001)
김한철 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.3
The Cl-saturated Si(001) surface is investigated by employing density functional theory calculations. From the electronic density of states, the low- and the high-bias filled-state images and the empty-state images are found to originate from Cl(3p) states directed in-plane, in parallel with the Si dimer row, and perpendicular to the surface (z), respectively. The bright triplet, which is a characteristic scanning tunneling microscopy (STM) feature of an unchlorinated bare Si dimer, is attributed to an occupied dangling bond state of the bare Si dimer that is hybridized with the neighboring Cl(3pz) orbital. The previously observed split-dimer feature is confirmed to be the dimer-bond oxidized structure. Finally, we suggest that the initial back-bond oxidation does not occur on the chlorinated Si(001) surface because it is energetically not favored compared with dimer-bond oxidation and because its STM simulation does not match experimental images.
원형편파로 급전되는 포물면 반사기 안테나에서의 빔 편이현상
김한철,김흥수 濟州大學校 工科大學 産業技術硏究所 1992 産業技術硏究報告 Vol.3 No.-
The beam squint phenomenon is an important factor to design parabolic reflector antennas. This paper aims to suggest the general squint-predicting formular and squint-free condition in circularly feed paraboloidal antennas. Squint-free condition is suggested to avoid the squint phenomenon that can be affect the antenna pointing performance in the long-distance communication, deep-space telemetry, radioastronomy, etc. Squint-free antennas can be designed by this squint-free condition.
修正 增分法환을 利用한 Deep Arch의 幾何的 非線形解析
김한철,민경주 대구대학교 과학기술연구소 2000 科學技術硏究 Vol.7 No.1
In this study we discuss modified incremental methods for geometrically non-linear analysis for path-following algorithms. For purpose we drive, base on a parametrization of the solution path. A unifed presentation of some popular continuation procedures used an analysis of structural mechanics in introduced. Updated weighting factors are introduced in the constraint eguation in order to get better convergence characteristics in the case when localized deformations occur.
김한철,김기대 대구대학교 (한사대학) 산업기술연구소 1985 産業技術硏究 Vol.4 No.-
This study is directed for the Optimum design for R.C footing section for the minimum cost design based on the strength design method of ACI(308-77). In this study, the design constraints based on ACI Code Provisions, such as flexural and shear constraints are taken as the constraints of the nonlinear formulation for the optimum design of R.C footing, and cost function including the material cost of concrete and reinforcing steel minimum cost design of structures are adopted as the objective function. The incremental linear programming technique is used as the optimization technique of the nonlinear Programming formulated in this study by Successively transformming nonlinear equations into the linear equations. It has been observed that the optimization model and technique computerized by FORTRAN Program for the optimum design of R.C footing proposed in this study significantly reduce the construction cost, when compared with the conventional design. Also, it has been proved optimization algorithm deviced in this study is very efficient for the convergence of optimization sections.
초등학생 태권도 수련방법에 따른 등속성 요부근력 및 체력비교
김한철,박기용,서민우,박영명,박정철,김동원 한국스포츠리서치 2007 한국 스포츠 리서치 Vol.18 No.6
This study compared isokinetic lumber muscle power and basic physical strength between 12 Taekwondo sparring players and 12 Pumsae players in grade schools. In order to measure isokinetic lumbar musle power, this study used Cybex 770(Cybex NormTM Test & Rehabilitation) isokinetic dynamometer to determine peak torque of lumbar extensor and flexor at 69°/sec, 90°/sec and 120°/sec. Measurement data were used to calculate mean and standard deviation of each group by means of SPSS ver. 12.0, while independent t-test was adopted for significance test. And significance level was set at ɑ=.05. According to the comparison of isokinetic lumber muscle power, it was found that sparring group showed higher muscular strength(at 60°/sec) and higher muscle power(at 90°/sec) than Pumsae group. For the basic physical strength, but sparring group showed higher levels in other test(Burpee test[squat thrust], shuttle run, push up, broad jump, and speed rope skipping). Summing up. it is concluded that grade school Taekwondo sparring plays have more excellent lumbar muscle power and physical strength than Pumsae players.